I used to be an ardent supporter of the death penalty . But today, I am the co-founder of L’chaim! Jews Against the Death Penalty, a group whose thousands of members stand against capital punishment in every case, without exception.

My change of heart took place over three decades, including years of service as a Jewish prison chaplain. Like many members of L’chaim who are descendants of survivors of the Holocaust , my lifelong struggle with capital punishment is intertwined with the legacy of that unparalleled mass murder. We know that while the Holocaust and the death penalty are entirely separate matters, the lessons about state killings learned from the Shoah have direct application to capital punishment, and we must heed these lessons to ensure that “Never Again” has any meaning at all.

The jury selection for the Pittsburgh Tree of Life shooter’s federal capital trial, which is set to take place in the next several weeks, has prompted some reflection on the connection between these two matters for me, as it has for many members of L’chaim.

Many of my childhood Passover Seders and Jewish/secular holiday gatherings were punctuated by my grandmother and her sister, who shared details of their Holocaust experiences . Their survival, and my very existence, would not have been possible without the martyrdom of Mr. Michal Cegielski, a Polish Catholic man who gave his life rather than give up the location of their hiding place on his farm. After decades of attempts to find this man’s identity, Cegielski now is rightfully honored in the Garden of the Righteous Among the Nations in Yad Vashem in Israel.

I believed during my formative years that anyone who had murdered my many other family members, or Cegielski, deserved to die. This logically extended to any human being who committed murder. As I saw it, lex talionis, the law of retribution, was clearly permitted by the Torah’s famous phrase “ayin takha ayin” (Lev. 24: 19-21), meaning “an eye for an eye.”

Not until my service as a Jewish prison chaplain in Canada did I seriously begin to explore the matter of state killings. I witnessed first-hand profound examples of repentance and change in people whose crimes might have qualified for the death penalty in various U.S. states. I explored how rabbinic Judaism made the death penalty extremely difficult to carry out. I came to understand what many modern-day Jewish authorities have realized: that the notion of capital punishment as a deterrence to any would-be murderers, which was a main justification for keeping it on the Talmudic books, has been disproven time and again.

Around this same time, I watched the execution of Troy Davis unfold in Georgia in 2012, and the reality that the state is not infallible, and that it can apply punishment to innocent human beings wrongly convicted, hit home. I learned about how at least 190 people who had been wrongly convicted or sentenced to death in the United States have been exonerated since 1972. Other human beings whose guilt remains under significant doubt have been executed as recently as March of this year. The clarion call of Jewish sage Rabbi Moses Maimonides on this matter offered much clarity: “It is better to acquit a thousand guilty persons than to put a single innocent one to death.”

Still, some doubts lingered in my mind. What about “the worst of the worst” offenders, or those, such as the Tree of Life shooter or Nazis, who committed deadly acts of terror?

Paradoxically, it took the shadow of the Holocaust itself to cast off my final misgivings. I discovered, to my shock, that the main form of execution that we use here in the U.S., lethal injection, is a direct Nazi legacy . Lethal injection was first implemented in our world by the Third Reich as part of their infamous Aktion T4 protocol, used to kill people deemed “unworthy of life” and developed by Dr. Karl Brandt, personal physician of Adolf Hitler. If this were not enough, American states continue to build gas chambers in prisons, with at least one state using Zyklon B to kill convicted death row inmates.

Jewish human rights luminaries such as Martin Buber , Gershom Scholem , and many others grasped the danger of giving the state the power to kill its prisoners long before I was born. They even opposed Israel’s 1962 execution of Nazi perpetrator Adolf Eichmann. Likewise, it was renowned Holocaust survivor Elie Wiesel who famously said of capital punishment: “Death is not the answer.”

Wiesel also said the following, which has become our anthem in L’chaim: “With every cell of my being and with every fiber of my memory, I oppose the death penalty in all forms. I do not believe any civilized society should be at the service of death. I don’t think it’s human to become an agent of the angel of death.”

Realizing that Buber, Scholem, Wiesel, and other Jewish and non-Jewish human rights leaders were aligned with this cause made my change of heart complete. The Holocaust had morphed from one of the greatest justifications for the death penalty to the most significant reason to stand against state-sponsored murder in every single case, even for the Tree of Life synagogue shooter .

If I could change my mind on this subject, so can anyone. I pray that one day, all human beings will join the sacred cause of abolition and chant together in one unified human voice: “L’chaim — to Life!”

Michael J. Zoosman is a board-certified prison chaplain, the co-founder of L’chaim: Jews Against the Death Penalty , and an advisory committee member for Death Penalty Action .